Great Smog of 1952 London still instructive / Thousands died in event that spurred environmentalism
Published 4:00 am, Sunday, August 17, 2003
In early December 1952, a great mass of cold air moved off the English Channel, draped itself over London like an icy comforter and stayed put.
Trying to keep warm, Londoners piled extra coal into their fireplaces, sending plumes of black, sooty smoke into the air that mixed with clouds of exhaust from factories and coal-burning power plants. But instead of rising into the atmosphere and dispersing, the smoke stayed close to the ground, trapped by the cold air above.
Over the next five days, a city already famous for its smog experienced the worst air pollution it had ever seen. A thick haze hovered over the streets, penetrating homes and offices. Public transportation nearly ground to a halt, and at night the visibility was so poor that some parts of London became unnavigable.
Indoor concerts were canceled because the audiences could not see the stage.
Then the smog lifted and the problems were over. Or so it seemed.
"There was no sense of drama or emergency," said Dr. David V. Bates, who at the time had just started work at St. Bartholomew's Hospital in London. "It was only when the registrar general published the mortality figures three weeks later that everybody realized that there had, in fact, been a major disaster."
PERHAPS 12,000 DEATHS
Some 4,000 people died of respiratory ailments in those five days, and perhaps an additional 8,000 in the months that followed.
Most of the victims were especially vulnerable by reason of age or illness.
Now a new study, based on lung tissue samples preserved from the victims of what became known as the Great Smog of 1952, has provided insights into why it proved so deadly.
It also illustrates the continuing danger of airborne pollutants known as particulate matter, experts said, for which environmental officials in the United States are considering new regulations.
Writing in the journal Environmental Health Perspectives, the researchers said they found high concentrations of fine particulate matter in the lungs of 16 people whose deaths were attributed to the smog.
The findings, lead author Dr. Andrew Hunt said, confirm the suspicions of the London health authorities from that period.
"The conception was it was the soot in the atmosphere, and coal-burning clearly the obvious culprit," said Hunt, who led a team of researchers from the State University of New York Upstate Medical University in Syracuse and the Royal London Hospital. He is now a consultant.
Coal combustion probably was the main factor in the deaths, the researchers said. But a close examination of the victims' lung tissue indicated that Londoners were exposed not just to high volumes of ultrafine carbon materials but also to more than a dozen other fine particulate substances, including metals like lead.
DIESEL FUEL PARTICLES
Perhaps more significant, the study found concentrations of particles associated with diesel fuel, which remains a major source of air pollution in Europe and, to a lesser extent, the United States.
The mass deaths occurred the same year that London completed its switch from electric trams to diesel buses, so it appears that a combination of factors may have made the smog so deadly, although the role of the metals is not yet understood.
The Great Smog is considered a turning point in environmental history. Although there had been other episodes where air pollution was held responsible for a spike in deaths -- notably in the Meuse Valley in Belgium in 1930, and in Donora, Pa., in 1948 -- the numbers were much lower than those in London.
In the aftermath, British officials passed laws banning the emission of black smoke and requiring industry to switch to cleaner-burning fuels.
"Once London hit, it was no longer deniable that air pollution was a big deal and that a small amount of pollution could have a big effect," said Dr. Devra Davis, a researcher at Carnegie Mellon University and the author of "When Smoke Ran Like Water," a history of air pollution.
While the danger of particulate matter has been demonstrated in many studies, the value of the new report, experts said, is the detailed portrait of pollution exposure it draws by using tissue samples.
When the Great Smog occurred, health officials did not monitor air quality, as they routinely do now. That is where the lung samples come in.
"It is allowing us to see what they inhaled," said a co-author of the study,
Dr. Jerrold Abraham of SUNY Upstate.
By looking at samples from different parts of the lungs, the researchers determined what the victims had been exposed to just before their deaths and over the long term. They also found that some potentially dangerous metals in short-term storage parts of the lung were not in long-term storage parts, suggesting that the metals had been absorbed, and supporting current theories about the dangers of inhaled metals.
Still, the findings are of much more than historical interest, experts said.
Janice Nolen, director for national policy at the American Lung Association, which helped pay for the study, said they reinforced the need to restrict emissions from diesel fuel and older factories that still burn materials like coal.
"We're still killing thousands of people, unfortunately, with fine particle pollution in this country," Nolen said.